Bone fracture fixation may involve using a structure to counteract or partially counteract forces on a fractured bone or associated bone fragments. In general, fracture fixation may provide longitudinal (along the long axis of the bone), transverse (across the long axis of the bone), and rotational (about the long axis of the bone) stability. Fracture fixation may also preserve normal biologic and healing function.
Bone fracture fixation often involves addressing loading conditions, fracture patterns, alignment, compression force, and other factors, which may differ for different types of fractures. For example, midshaft fractures may have ample bone material on either side of the fracture in which anchors may be driven. End-bone fractures, especially on the articular surface may have thin cortical bone, soft cancellous bone, and relatively fewer possible anchoring locations. Typical bone fracture fixation approaches may involve one or both of: (1) a device that is within the skin (internal fixation); and (2) a device that extends out of the skin (external fixation).
Internal fixation approaches typically involve one or both of: (a) a plate that is screwed to the outside of the bone; and (b) an implant that is inserted inside the bone.
Plates are often characterized by relatively invasive surgery, support of fractured bone segments from one side outside of bone, and screws that anchor into the plate and the bone.
Implants may include intramedullary rods or screws, such as those used in mid shaft treatments. The typical intramedullary rod or screw is fixed in diameter and is introduced into the medullary canal through an incision. Flexible intramedullary rod-like solutions utilize structures that can be inserted into the medullary cavity through an access site and then be made rigid. The flexible structures may be reinforced with polymers or cements. Multi-segment fractures, of either the midshaft or end-bone, may require alignment and stability in a manner that generates adequate fixation in multiple directions. Implants may be used to treat midshaft fractures and end-bone fractures.
Implant-based therapies may involve removing or displacing bone tissue from the interior of the bone to prepare the interior for the implant. Preparation for the implant may involve providing a space in the bone interior for reception of the implant.
Various tissue densities may be present within a bone. Tissue density may vary within different anatomical locations and from person to person. A bone defect or fracture can further vary tissue density based on a density of tissue surrounding the bone defect or fracture. Manipulating this tissue in a controlled and efficient manner, while imparting minimal energy, is desirable for therapy.
Proper location, size, shape, orientation and proximity to bone fragments and anatomical features, among other factors, may increase the therapeutic effectiveness of the implant.
It would be desirable, therefore, to provide apparatus and methods for preparation of a bone interior.